When converting your document to PDF, sometimes your images may not appear in the conversion.
There are two options to solve this issue:
Saving document as PDF (as opposed to Print to PDF)
1. Click File -> Save As
2. Select the file type "PDF (*.pdf)", name the file, and select the location to be saved
3. Click Save button
If the problem persists...
Try using JPEG files (.jpg) instead of PNG (.png)
1. Convert your "PNG (*.png)" images to "JPEG (*.jpg)".
If you have tried both methods above and you're still encountering issues regarding your images, please contact firstname.lastname@example.org for further assistance.